There were no swords doubling as carving knives, such as the one featured in the restaurant’s last reopening in 1976 under restaurateur Warner LeRoy. There were no gigantic sundaes or 16-foot long cakes. And it was far too cold for bikinis.

The loudest noise came from whistles screeching from a crowd of union protestors. Instead of animal topiary, customers were greeted by a giant inflated rat.

“Just more bells and whistles,” said proprietor Jim Caiola with a strained smile.

It was all part of the new low-key Tavern concept. By 7:30 p.m., the restaurant was pleasantly full with reservation-holding customers and bar walk-ins, but was hardly crowded, with couples and friends tucked into low booths by the bar. Quiet conversations filtered through the room over a mellow soundtrack of Norah Jones and Frank Sinatra. Tavern officials said they served 557 diners Thursday.

In other words, Tavern slid seamlessly into position as an upscale neighborhood restaurant, nestled at the edge of Central Park. Still, the restaurant is sold out for the next two weeks, a spokesman said.

Guests arrive at the new Tavern on the Green restaurant Thursday.

Peter Foley for the Wall Street Journal

“This is like a preview,” said David Salama, Mr. Caiola’s life and business partner, who helped oversee the restaurant’s multimillion dollar overhaul. A gala on May 12 “will be the big blowout,” he said.

Some guests didn’t even realize they had snagged a seat on opening night.

“Is today the first day?” asked Elske Parker, a 37-year-old from Hoboken who was there celebrating her mother’s 76th birthday at the bar. “Oh my God, I cannot believe [it].”

Her mother, Pia, said she “didn’t have much hope to get in” when they arrived, but was pleasantly surprised. She had visited the restaurant decades ago and was eager to see it again.

“This is lovely,” she said. “And my martini is great.”

At its peak, Tavern was the highest grossing restaurant in the country, earning $37 to $38 million in revenues a year. But by the time the license agreement with the city expired in 2009, the place had fallen into disrepair.

“It had really gotten shabby,” said Bill Wynne, 61, who strolled in to grab a drink at the bar with his wife, Barbara.

The couple live across the street and christened their son at the restaurant in 1991. “We have fond memories of the place,” he said. “It’s a delightful reemergence in the neighborhood. I think it’s fantastic. They’ve scaled it down but made it more interesting.”

The only thing they miss?

“The lights,” said Barbara with a sigh, referring to the lights that once encircled tree branches but are no longer allowed by the city. The couple planned to come back on Monday for a birthday party, and again on Tuesday for a date night, they said.

“It’s all neighbors,” Mr. Salama said. “They haven’t had that for many, many years.”